Mullins, a native of Lexington, Kentucky, was a very talented 6'4" (1.93 m) forward in high school. After graduation, he attended Duke University from 1960 through 1964, where he averaged 21.9 points per game for his career. His #44 Duke jersey was retired in 1994.
In 1985, Mullins was hired as the head men's basketball coach and athletic director at UNC Charlotte. The program had struggled since making the NCAA Final Four in 1977, and in three years Mullins took the 49ers back to the NCAA Tournament for the first time since their 1977 run.